This invention relates to glass production and, more particularly, to an electrode block for use with an electric furnace. It is intended that the term "electric furnace," as used herein, denotes both electric melt and electric boost furnaces.
Electric glass melting furnaces have a plurality of submerged electrodes that are positioned in the furnace in a predetermined pattern. An electric current is caused to flow through the molten glass between the electrodes to heat the glass by the Joule effect. The electrodes are inserted through electrode blocks in the bottom wall of the furnace; generally, such electrode blocks are rectangularly shaped and are made of fused cast refractory, such as alumina and zirconia. A significant problem that has occurred in the operation of such furnaces is the difficulty encountered when the electrodes are raised or inserted into the furnace. Quite often a great deal of upward force has to be exerted by the electrode jack in order to move the electrode through the aperture in the electrode block. This increased force causes the block to loosen and hence tend to slip out of place, thereby making it difficult to insert more electrode into the furnace. In addition, if the block is moved out of position, more of the top surface of the block is exposed to the glass, thereby accelerating wear of the block.
Therefore, it is an object of the present invention to provide an electrode block for use in the floor of an electric glass melting furnace that does not tend to loosen or move when an upward force is exerted on the electrode.